Contaminants in aquatic sediments and detritus can include oil and hazardous materials, toxic metals, and nutrients like phosphorus, nitrates and sulfates. Some of these contaminants readily absorb to suspended organic and inorganic materials or seston in water. Some of the contaminants, particularly the nutrient phosphorus, can be taken up and used by aquatic biota including benthic and pelagic algae, cyanobacteria, and plants. Eventually, the contaminants of interest to this invention are those that settle out of the water column to form a very loose, detritus layer on sediment that can be easily resuspended, dispersed or released in a soluble, solid, or colloidal form back into the water column by physical disturbance, diffusion, microbial and geochemical processes, or the actions of aquatic biota.
For the purpose of this invention algae, cyanobacteria, and invasive, noxious and nuisance densities of aquatic plants or animals are also considered contaminants that can be targeted by this invention for control or removal from water bodies.
Contaminants in sediments and detritus can also concentrate in ecologically sensitive, littoral regions of water bodies that could be adversely impacted by other dredging methods or application of chemicals or clay to treat or bind contaminants. Similarly, contaminants can also be located in shallow water containing invasive, noxious, or nuisance densities of aquatic plants, algae and biota that could be spread further throughout the water body if other dredging methods or treatment with chemicals were used. Shallow water areas are also not conducive to the use of chemicals to treat contaminants or for clay to bind or cover contaminants due to wave action and water turbulence often found in shallow water areas.